1. Field of the Invention
The invention relates to the field of payload dispensing systems for aircraft and the like and, in particular, to a simplified payload dispensing system that both ejects and guides the payload during separation.
2. Description of Related Art
On low speed, subsonic aircraft, weapons, whether carried on the wing, underside of the fuselage or within a weapon bay, can be gravity dropped with acceptable separation characteristics. The weapons are released from the bomb rack and armed after release. The very early aircraft used mechanical means to accomplish release, while more modern aircraft use solenoid or power operated hooks. But, with high-speed jet aircraft, which fly at high subsonic and supersonic speeds, gravity weapon release, particularly from an internal weapon bay is dangerous and can result in unpredictable trajectories. This occurs because at the high level of air turbulence about the aircraft at supersonic speeds. In addition, shock waves are formed which exacerbates the problem. Thus, the weapon must be physically ejected.
A typical bomb rack comprises hooks for suspending and releasing the weapon, sway braces for stabilizing and hydraulic or explosively actuated ejectors. In operation, the release cycle takes but milliseconds from the time the weapon is released to the forcible ejection. The ejectors can be programmed so as to vary the force at which the missile is ejected and also the pitch angle (different force levels in each ejector). Typical ejectors are disclosed in U.S. Pat. No. 4,399,968 xe2x80x9cControlled Output Force Actuatorxe2x80x9d by Stock et al. and U.S. Pat. No. 4,257,639, xe2x80x9cEjector Device for Storagexe2x80x9d by Stock. By forcibly ejecting the weapon the exposure to turbulent airflow is kept to a minimum and the weapon will have considerable momentum so as to pass quickly through the turbulent air. This provides a more positive means of safe separation. The disadvantage is that during ejection the weapon immediately loses contact with the sway braces and stabilizing is solely dependent upon the force applied to the weapon.
Another approach is to mount the rack on a four bar link assembly and lower the weapon out of the weapon bay prior to ejection. This provides stabilization and does position the weapon away from the aircraft. But, when launching missiles it is desirable to provide not only safe separation from the aircraft, but a forward velocity thereto. While the extension of the parallel links and solenoid operated hook release could be coordinated so that such a directional thrust is obtained; there would always be the possibility that the weapon would be lowered but the hooks failing to release. The resulting loads on the links and supporting structure would be quite large. Therefore, it would be desirable to have automatic mechanical release.
Such a system was disclosed in U.S. Pat. No. 4,679,751 Weapon Dispensing System by P. Peterson. This system includes a weapon positioning assembly for positioning the weapon in a stored position and a release position. The weapon positioning assembly comprises a weapon support rack and a pair of fore and aft links having first and second ends. The first ends of the links are pivotally coupled to the aircraft and the second ends are pivotally coupled to the rack. An actuator assembly is coupled by its first end to the aircraft and by its second end to the weapon positioning assembly. It is adapted to move the positioning assembly from the stored position to the release position. Fore and aft weapon-attaching devices for releasably locking the weapon to the rack are attached to the weapon positioning assembly. The weapon releasing devices are adapted to lock the weapon to the rack when the weapon position assembly is in the stored position and to only unlock the weapon when it is in the release position. Thus, upon actuation, the rack, with the weapon locked thereto, is rotated in a downward and forward direction and automatically released when the release position is reached. This system, as well as the other prior art systems that deal with ejecting explosive weapons, are complicated and expensive.
Thus, it is a primary object of the subject invention to provide a dispensing system for ejecting a payload from an aircraft maintaining a positive positional control throughout the ejection stroke.
It is another primary object of the subject invention to provide a payload dispensing system for an aircraft wherein the payload can be stored internally and positive positional control is maintained until the payload has cleared the interior of the aircraft.
Another object of the subject invention is to provide a payload dispensing system for an aircraft wherein the release of the payload is automatically accomplished by mechanical means.
The invention is a payload dispensing system for an aircraft. In detail, the invention includes a housing mounted to the aircraft. A hollow shaft is mounted to the housing having an open first end and a closed off second end with a hole therethrough. The payload includes an aperture having a first end on an external surface thereof and a second end terminates in the interior thereof. A restraint system releasably secures the payload to the housing such that the hollow shaft extends into the aperture of the payload. Preferably, the restraint system includes an endless cable assembly extending about a first pin mounted in the second or bottom end of the aperture in the payload, extending through the hollow shaft and about a second pin mounted to the housing.
A compression spring is mounted at least partially within the hollow shaft, having a first end in contact with the end of the hollow shaft and a second end in contact with the second or bottom end of the aperture. The spring has a compressed position when the hollow shaft is within the aperture and asserts a force tending to separate the payload from the aircraft. A cable cutter is mounted on the housing for releasing the payload from the housing, such that upon cutting of the cable, the spring forces the payload away from the aircraft and the hollow shaft guides the payload during separation.
The payload dispensing system further includes a payload tensioning system for adjusting the tension load on the endless cable to insure that the payload is rigidly attached to the housing. This is accomplished by incorporating a threaded hole in the second pin and having the second pin movably mounted within a slot in the housing. A threaded screw is rotatably mounted within the housing and extends through the slot and also engages the threaded hole in the second pin. Thus as the threaded screw is rotated the second pin is translated in the slot such that it applies a tension load to the cable assembly.
A cable cutter assembly is provided for cutting the cable allowing the payload to separate from the housing. In one embodiment, a rotary actuator is mounted on the housing having an output shaft. An arm assembly is attached by a first end to the output shaft of the rotary actuator and a second end attached to knife blade; such that rotation of the output shaft moves the knife blade into contact with the cable assembly severing same and releasing the payload.
The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages thereof, will be better understood from the following description in connection with the accompanying drawings in which the presently preferred embodiment of the invention is illustrated by way of example. It is to be expressly understood, however, that the drawings are for purposes of illustration and description only and are not intended as a definition of the limits of the invention.